We propose to work on the following problems in our study of antibody formation. 1. The proportion of cells which respond in the rabbit to antigen stimulation by producing IgM, IgG, or IgA. We also intend to determine how the injection of lippolysaccharide or endotoxin effects this proportion. And in the mouse the proportion of IgE in such a response. We hope to manipulate the number of IgE cells.